Revert "can: statistics: use atomic access in hot path"

This reverts commit 68adc6f1 which is
commit 80b5f901 upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: Iffc58c5315d0bdeef4e53cb5dae8ec539743a89c
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>